Fever is frequently the only clinical sign of infection in patients with chemo-induced neutropenia. In this setting, empirical administration of broad spectrum antibiotics must be rapid. The aim of this work was to compare, for the first time, cefpirome (CPO) and piperacillin-tazobactam (PT) in a large randomized trial. Two hundred-eight febrile neutropenic episodes (FNE) (> or = 38.5 degrees C and ANC < or = 0.5 giga/l) were treated by randomization, as first line therapy, using either CPO 2 g x 2/day (105 cases) or PT 4 g x 3/day (103 cases), alone (CPO: 15/PT: 15), or plus aminoglycoside (165 cases, CPO: 82/PT: 83) or quinolone (CPO: 2/PT: 2). There were 131 men and 77 women aged between 17 and 83 years (median: 49) who received chemotherapy (n = 160) or allogeneic (n = 10) or autologous (n = 38) stem cell transplantations. Underlying diseases were: acute leukemia (n = 131), lymphoma (n = 33), myeloma (n = 16), solid tumor (n = 8), myeloproliferative disorder (n = 9), chronic lymphoid leukemia (n = 5), aplastic anemia (n = 3), myelodysplasia (n = 3). Distribution of age, neutropenia duration (median: 17 days), underlying disease, and protocol therapy duration (median: 11 days) was comparable in both arms. A microbiologically documented infection (MDI) was evidenced in 57 cases (27%). Bacteria were isolated from blood cultures in 54 cases (Gram positive: 32 cases). Their in vitro susceptibility rates to CPO and PT were not different. Two days after antibiotics initiation, clinical (fever disappearance) and microbiological (culture negativation) success rates (SR) were 62% for CPO versus 61% for PT and 50% versus 55% respectively in case of MDI (p = 0.89). Two deaths and 77 failures were registered. At the end of protocol, SR (no antibiotic change/absence of superinfection) was 59% with CPO versus 50% with PT (p = 0.27) and 53% versus 40% respectively in the 151 cases with neutropenia > or = 10 days (p = 0.17). The occurrence of side effects was similar in both arms. In our hands, the efficacy of CPO and PT was comparable for treating FNE.